GSA Annual Meeting in Seattle, Washington, USA - 2017

Paper No. 79-4
Presentation Time: 9:00 AM-5:30 PM

VOLCANICLASTIC DIKE OF THE SOUTHEASTERN UINTA BASIN


ROBERTSON, Westan A and MCCONKIE, Spencer, Geology, Southern Utah University, 351 W University Blvd, Cedar City, UT 84720, westan@live.com

This study is being conducted to investigate a dike that is located within the Uinta Basin near the southeast corner of Duchesne County, Utah. There has been little to no work done on this structure; thus there are three primary goals for this project. The first is to determine the composition of the dike itself. The second is to determine the dike’s origins and if there are similar structures in the surrounding area of the structure. Finally the overall goal is to determine a viable model for the intrusion or injection of this structure.

Based upon the compiled data the dike appears to be comprised of volcaniclastic material injected by the weight of burial applied to an overlying ash deposit. The structure along with the with ash deposit both occur within the Green River Formation (GRF). Thin section analysis of both the ash deposit and the dike indicate they are of similar intermediate composition. This data combined with the downward wedge geometry of the dike indicates the likely source of material for the dike as the overlying ash layer. The area appears to be fairly flat lying with little strain evident. Some small structures (conjugate fractures and pencil structures) indicated a primarily vertical orientation of maximum compression, though without further work their relationship to the dike cannot be determined.

Future work planned is to further investigate the tie between the located structures, the tie between the ash and the dike, and a brief exploration into the provenance of the volcaniclastic material. Through a more detailed chemical analysis using thin sections and XRF data we can gain a more detailed chemical composition to compare the ash, dike, and other proximal volcanic eruptions. We plan to conduct a more thorough structural investigation to map out the paleostress in the area to confirm the orientation of maximum compression and compare the strain in the area to the dike. Finally we would like to do some further field exploration to locate any similar features near the dike for future projects or as additional data should it be needed.